1. Field
Example embodiments of the present invention relate generally to wireless networks and transitioning between wireless networks of different protocols.
2. Description of the Related Art
CDMA2000 EVDO and 3GPP LTE are two different protocols that may be used in wireless networks to support the transmission of IP data packets to and from mobile devices connected to the wireless networks. An operator that deploys a CDMA2000 network and would like to configure the CDMA2000 network to facilitate the transition of a mobile device communicating with the CDMA2000 network to the LTE network and back will be presented with a number of interoperability problems.
Due to differences in data transmission speeds between the wired internet and wireless networks, when a target mobile device is active on a CDMA2000 network, IP packets received at the CDMA2000 network for the target mobile device are buffered until the target mobile device is prepared to receive them. If the target mobile device transitions from the CDMA2000 network to the LTE network before the buffered data packets are forwarded to the target mobile device, the buffered and unforwarded data packets will be lost.
Similarly, when a target mobile device is active on an LTE network, IP packets received at the LTE network for the target mobile device are buffered until the target mobile device is prepared to receive them. If the target mobile device transitions from the LTE network to the CDMA2000 network before the buffered data packets are forwarded to the target mobile device, the buffered and unforwarded data packets will be lost.
A target mobile device receiving data packets on a CDMA2000 or LTE network may be engaged in a TCP session with one or more other devices. The TCP protocol uses congestion control algorithms to inhibit congestion on a network by limiting the rate at which data is sent once congestion is detected. If the target mobile device is engaged in a TCP session with another device when the target mobile transitions from a CDMA2000 network to an LTE network or an LTE network to a CDMA2000 network, the loss of one or more packets may be interpreted by TCP algorithms as an indicator of network congestion. Accordingly, the loss of the buffered and unforwarded data packets may trigger a significant reduction in the speed with which data packets are sent to the target mobile device resulting in substantial delays.